Edge illuminated sign



Nov. 11, 1952 FUCHS 2,617,221

EDGE iLLUMINATED SIGN Filed Aug. 5, 1948 3 Sheets-Sheet l o 1 I T O INVENTOR. Paul E. Fuc hs ATTORNEY Nov. 11, 1952 FUCHS 2,617,221

EDGE ILLUMINATED SIGN Filed Aug. 5, 1948 3 Sheets-Sheet 2 ElG.-22

INVENTOR. Pou I E. Fuchs ATTORNEY shown inFig. 1';

Patented Nov. 11, 1952 UNITED stares ears? EDGE ILLUMINATED SIGN Paul E. Fuchs,"Coloraclo Springs, Colo.

-App1ication August 5, 1948, Serial N 0. 42,703

1 Claim. 1

=My. invention pertains to signs, and relates more particularly "to signs .of the edge-illuminated type such asithose formed from acrylic resins. This application is related to myco-pending application, Serial No 32,909, filed June 14,1948.

One of the principal objects of my invention is to'providean edge-illuminated sign in which a :pl-uralityof light-transmitting plastic plates of relatively large dimensions, each bearing an engraved legend, may-be uniformly illuminated-at high intensity with light of similaror contrasting colors.

Other objects of my inventioninclude the provision of improved methods and devices for sealing the edges of suchtsigns against the entry of foreign material, for-engraving-legends on the signs'in such manner that the size ofthe legend .appears uniform to the eyeregardless of variations in the intensity ofillumination and for assemblingicompositesigns in an efficient, inexpensive, and durable manner.

Further objects of my invention include the provision of an engravingguidewhich is of mavterial assistance to an operator in formingthe to 'thediverse novel formationsand arrangements of parts and to thevarious methods employed,

will be disclosed-in the course of-the following description taken :in conjunctionwith the appended drawings in which:

Fig; 1 is an elevation; of edge illuminated sign incorporating my invention; Fig.2 is a partial front ,elevational view, partly broken away, of the central portion .of the-sign housing for use with my sign;

Fig. 4 is a cross section taken along the lines ll-tinEie. 2;

Fig; 5 is apfragmentary section corresponding to the fragmentary sectionsjshown in Fig. 4; and

positioned, at; 90 to the. showing 1in-'Fig., 4, illustrating. the application ofzaebackin v:nlate .to the ppperplate;

Fig. 6. is ajiragmen'tary section; corresponding Fig. 7 is a view similar to. Fig: 6, i1lustrating a modified form of reflective strip and plastic members in association with the upper plate;

8 is .an elevation of .armodi-fied form of my I S n;

plate .21, shown in Fig.

. source through an .gravedlegend orindicia formed in the plate. In

. conventional signsof this nature. a

.. the source of i1-1urnination,.creating pleasing highlighteflecttatnese .jportions, but

-.-Fig; 9 is a fragmentary cross sectional-view; on

ture'taken approximately in a position corresponding to line 9-9 of Fig. 8

Fig. 10 is'a viewsimilar to Fig. 9 but illustrating a somewhat further modified form of structure;

1L isa; sectional view of ,a modified form of strip used in'the fashion .of the strip shown m ne. 10;

.-F i g."12 is a viewsimilar to Fig. lland illustrating-a further modified form of strip;

Fig. 1-3-is a plan view of an engraving guide;

14 is a cross section taken along the line .guides arranged onasui tah-le .backing plate;

Fig. 16 is anedgeelevational view of a tool for use with my engraving guide;

-.F ig. 16A is a front elevational. view of the tool shown in Fig. 16.; i

Fig. 17 is an elevational view of another tool for .use with my "engraving guide;

. Fig.5l8 is a iraginentary cross-section of the 4=, employing my improved form .of engraving and. drawn ,to an enlarged scale;

Fig. 19 is an elevation Of a suitable tool for en ravin my i n;

Fig- 20 is an end view of the tool shown Fig. 21 is an elevation of .a tool shown in Figs. wand 20;

Fi .,22;is,a partial plan view of a modifiedjform of plate 'formy sign;

Edge-illuminated signs formed from sheets or --plates of aplastic such as the hard acrylic resins -have been known for severalyears and utilized the .unusuallight-transmitting characteristics of such materials to convey light from a suitable edge of the vplate.to ako.en-

, sr prf p rtion-of the light entering the sign isijnte'rcefpted by the ortions of the legenddisposed closest to a. sometimes leaving the remainder of the legend very dimly illuminated. This characteristic, .plus the "inev- 3 itable loss of light in transmission and edge radiation has limited both the maximum size and use of such signs.

I have found these and other undesirable effects can be largely overcome and the maximum over-all size of the sign substantially increased by disposing a lamp or other suitable source of illumination between especially formed edges of light-transmitting plastic plates, which form in combination a complete sign. The edges nearest the source of illumination are formed to diifract the incident light rays entering the plate in a plane parallel to the plane of the plate, and reflective surfaces are provided on the other edges of the sign to reflect light into the plate which would otherwise be lost. As a result, substantially all of the light entering the edges of the 'plate is used for the illumination of the legend and yields a substantially uniform degree of illumination having remarkable brilliance.

Because of the osition of the source of illumination with respect to the legend, and also because of the reflective edges and formed edges, I am able to adequately'illuminate a much larger area than has heretofore been considered practical in edge illuminated signs.

A backing plate 20 may be mounted in contact with the back or engraved surface of the plates 2| and 22 to intensify or vary the appearance of the legend 53. If the sign is to be continuously illuminated, the plate 20 may be of opaque material of any desired color, whereas if illuminated only on occasion, transluscent or transparent plates 20 may be provided. The contrast thus obtained, particularly with colored opaque or transluscent sheets 20 is striking, and increases the flexibility of my sign.

I may also apply a suitable dye of any desired color to all or any portion of either the face or back of the plates 2| and 22, or in certain instances, a paint may be substituted for the dye. Usually, a dye applied evenly to the face of the sign is the most effective, and eliminates the need for colored sheets or plates.

Since the high brilliance of the legend obtained in my signs under artificial illumination imparts to the legend formed in the plate an apparently greater size as compared to the same legend when illuminated only by daylight, I provide a special rotating tool for forming or engraving a new and improved form of legend, in which the apparent increase in size due to the high brilliancy is largely compensated. This I accomplish by forming a relatively shallow but wide groove or trough superposed on the conventional troughshaped engraving, with the result that thedeeper portions of the engraving intercept the major quantity of the light rays entering the edge from an artificial source, but the full width of the shallow groove is visible under daylight illumination, particularly when viewed from the front of the sign.

As an aid in forming the engraved legend, I provide flexible strips of a pressure sensitive adhesive material having a. non-adhesive surface, preferably grooved to receive the guide pin or tracing member of a pantograph or engraving machine. The legend or indicia may be formed from these flexible strips by arranging the strips in the desired manner on a suitable support and subsequently following the groove in the strips to reproduce the legend on the plate. If an error is made in laying out the legend with the flexible strips, correction is asimple matter due to the use of a pressure sensitive adhesive material.

For more detailed description, reference is made to Fig. 1 in which I have illustrated a simple form of sign incorporating my invention. My sign comprises an upper plate 2| and a lower plate 22 spaced apart a distance sufficient to receive a suitable tubular lamp 23. The plates 2| and 22, which may be on the order of threeeighths to one-half inch in thickness are formed of an acrylic resin such as methyl methacrylate or cyclohexyl methacrylate and possessing the characteristic of transmitting light from edge to edge parallel to the plane of the sheet in addition to transmitting light from face to face in the manner of ordinary transparent materials, this characteristic being herein termed light-transmitting as contrasted with transparent.

The edge of each of the plates 2| and 22 selected for disposition near th lamp 23 is provided with a series of flutings or scallops 24, shaped in such manner as to cause a diffraction of the light rays entering the plate through the fluted edge in a plane generally parallel to the plane of the plate. The scallops 24 may therefore resemble portions of a right cylinder having its axis perpendicular to the plane of the plates or other similar shapes.

The lamp 23 is preferably of the hot cathode fluorescent type adapted to operate without the generation of appreciable quantities of heat, thus permitting placement of the lam in close proximity to the edges of the plates 2| and 22. I also prefer to select a lamp having a diameter approaching the thickness of the plates to avoid waste of the light emitted by the lamp.

Lamp sockets 26 of conventional design are mounted in a trough-like metal housing 21 having side flanges 28 and end flanges 29. The height of the side flanges 28, plus the width of the housing 21 should be sufficient to overlap the scallops 24 formed on the opposed edges of the plates'2l and 22, when secured to the back of the sign. A suitable ballast and/or reactor 3| may be mounted on the housing 21 or disposed in other convenient location. A cover 32 having end flanges 33 and side flanges 34 in the same plane is secured to the face of the sign and is provided with a raised central portion 36 dimensioned to fit over the lamp 23 and sockets 2B. The over all width of the cover 34 is similar to the over all width of the housing 21 and is mounted on the sign in alignment with the housing by suitable bolts 31 extending through the cover 32 and the housing 21. The plates 2| and 22 are preferably somewhat longer than the over all length of the lamp 23 and the sockets 26. I therefore provide opaque spacers 38 for disposition between the end flanges 33 and 29 to prevent the undesirable transmission of light between the plates 2| and 22.

The spacers 38 may be provided with a suitable opening 39 to permit passage of the bolt 31, and

may also have reflective surfaces 4| in contact with the edges of the plates 2| and 22. Suitable edging 42 extends around th external edges of the assembled sign and fits closely to the plates 2| and 22, preferably overlapping the end flanges 33 and 29. Corner plates 43 having aligned openings for bolts 44 are provided on each of the corners for holding the sign and edging 42 in assembled position, the lower corner plates being provided with feet 46, if desired.

For indoor use, the edging 42 may suitably be of aluminum or similar material having a highly reflective internal surface in contact with the edge of the plates, the object of this structure epit et n being to refiect' back into the sign light 'which would "otherwise escape through the exposed edges. If,however, "the sign is "to be exposed to the weather or dustymonditions, I prefer --'to "employ-a structure "of the typeillustrated in Figs. '6 and'l. "As-shown iii-"Fig. 6, :I'may secure a-strip 41' of material *havinga highlyfreiiective surf-ace on the edge of theplate 2 I bypl'astic members 48 having laterally-extending sections -49 engaging the"strip*"41. The-members 48 -ma yibe sealed to the plastic plates! "or 22 by the suitable application of heat, solvents, or-adhesivesg thus providing *a water-proof "and dust-'tight seal' tor the edges, I i i As illustrated in- Fig. "7, members '5l may be provided-withaligned grooves 52 to receive the -edges'of the strip 41"and securec'l- -to the'plates-zl in similar manner. H

ll-legend or 'indicia 53"-may be-rormed o-n the plates '21 and 22 by engraving the'i'ear surface ofth'e plates. The trough or 'groove formed b'y engraving may beeither U-shaped-or V-shaped and ordinarily should'not-be of a depth greater than half the depth of the plates 2| or 22. Although I mayuse conventional engraving-of the -'type*described, -I 'prefer to employ engraving of "the type-illustrated in' Fig. -l8,-wherein I provide a- U-shaped or a V-sliaped-g'roove 54 formed in the rear surface ofthe-plateand'preferably extndirig not more than-half way-into the :plate 2-1 Near the rear surface of the .plate 2 I I form a superposed countersunk or enlarged portion 56 over the grooves '54., which is very shallow, but extends Elaterally' in both directions beyond the extremities .of the groove .54. A groove of this nature may best be formed by employing a tool of the type illustrated in Figs. 19 and 20 having a shank 51 and a head 58. An axially disposed crest 59 is formed-on .theiextrem'ity of the head 58, which is. preferably flattened as indicated in Fig. 19. One side of the head 58"extends outwardly as at [6, terminating in a shoulder 62 normal to the" axis or the tool. The face 63 of the tool defined by the relatively flat surfaces of the shoulder 62 and the sloping portion extending to the shoulder from the crest 59- may be inclined at-a slightangle to form -a cutting edge. The --tool may be mounted by theshank 51 in a suitable engraver or otherwise rotated to form the desired type of engraving. .As applied-to the plate, it may be seen that-the crest 59 of the .tool forms the basisof the-groove 54, while the shoulder 62-engraves the counter-sunk portion 56.

Light traveling through the plate 2| parallel to the faces will be intercepted primarily by the groove 54, which extends into the plate 2| a substantial distance. The counter-sunk portion 56, being shallow, will interceptonly a minor portion of this light but will be visible when viewed from-the front surfaceof the sign under even poorillumination. Thus the effect of increase in size of the legend due tothe high brilliance imparteddto the groove 54 is largely compensated by Jth'eaddition of thesurrounding counter-sunk -jp'oftion 5.6, which is more dimly illuminated, and the l'egendwill appear approximately the same dimensions regardless of the intensity of illumination.

It is possible to obtain a great number of varied and pleasing color effects with my sign through the proper application of transparent colored films of material. For example, a central portion 36 of the cover 32 may be provided with one or more slits 64. A channel-shaped, transparent, colored plastic channel 66 having a web 61 and .graved' on its rear .face.

sides- 68 may be fitted-over the lamp 23 a-nd held in place' either by suitableclips orby the natural resiliency of the material. The channel 66*nray be of uniform color, in which instance the legend on-the plate 2 l, the legend on the plate -22, and

the slitsfilwill all be illuminated with thesame since strips-"may be suita'b'lysupported on onnear the edges of thie -plates 2hand-22 'for -this purl:may a'lso indenti sections of'the c'entraI- por-- tion '36,:as indicated -at 69,-to receive a hat strip 11 of transparent colored material, -or a-s'trip 'n having --"a curved portion 13 r projecting into th'e slit 64. Alternatively, a strip" may be masked in part b'y stri-p 16 of opaque ortranslucent mater ial to definea somewhat lnarrowerzvisible :por-- tion, .see Fig. 12. :Similarly,the stri 16 maybe .appliedto strip .12 asiindi'cated in 11.

It will :be understood that thelege'nds' of sig'n's must be ordinarily spaced-to prov-idea balanced and pleasing effect toathe-iassemblyzand ..that 'l may dispose the lamp or lamps 23 z'inzanyxonelor more of these spaces. a The same lamp, therefore,

.in-most instances contributes at least :a. :portion of its light :to .twoplastic sheets-rather than' 't'o one, as. in conventionalsigns, with the result that the distance between :lampscan be at least doubled without sacrifice of brilliance. Anydesired numberzof sheets or plates may-thereforerbe employed edgewise to the lamp or bumps 23. To illustrate further this application ofmyfinvention, I .have shown in Fig. 8. .arelatively larges'ign comprising aqplate 16 bearing :aelegend .11 ten-- Covers 18,. similar to cover 32, are mounted over lam-ps disposed :along the upper and lower "edges'of theyplate 16; these edges being-provided with scallops 24 espreviously described. Relatively long and narrow plastic plates-19 may 'besecured in position on the :outer sides-of the lampsin opposed relation tothev plate 16 by suitable (edge channels 8| and also provided with engraving 82.. Corner plates 83, similar to those previously described, may-be employed to lock the sign together. As the lamps are illuminated, it will-be seenthat both plate-16 and the'plate 19:will be illuminated'and-tha-t the light from each of the lamps need penetrate the plate 1-6 .foronly half of its height. The plate 16 may therefore have 'a height at least twice as great as that which would otherwise be-;permissible for the same intensity of illumination.

Difiicultyis often encountered in obtaining the proper configuration of the legend oi -the sign regardless of the type of engravingtool or pantograph employed. I-ha-ve found that this difficulty can be largely overcome through the use 'of flexible strips of material -16 having a flat lower surface 86 coated with a pressure sensitive adhesive. The upper surface "81 .-is preferab y of a smooth non-adhesive -character and-may be provided with a longitudinal groove 88 in which the guiding pin of a pantograph or engraving machine may be placed. Strips of this material may therefore be applied to a suitable backing 89 and bent as desired to form the legend. Relatively straight strips such as those indicated in Fig. 13 may be applied to the backing 89, see Fig. 15, in combination to form angular letters, the grooves 88 in each of the strips being connected as at 98 by appropriate use of a suitable tool such as that indicated in Fig. 16. This tool comprises a shank 94 having a wedge-shaped head 91 by means of which a portion or the strip 84 may be depressed to connect the groove 83 with a similar groove in another strip. A pointed tool 96 may also be employed. Once the strips 84 have been properly arranged on the backing 89, it is a simple matter for an engraver to follow the grooves 89 to reproduce in either an enlarged or reduced form the desired legend. Errors occurring in the placing of the strips 84 are easily corrected, since the strip 84 may be lifted from the backing 89 and reapplied in a corrected position without disturbing other portions of the legend. Once formed, the engraver may retain the backing 89 with the legend applied for future use or may remove the strips 84 from the backing 89 for subsequent use in the formation of other legends.

It is not essential that the precise edge configuration illustrated at 24, lijig. 2, be applied to obtain a satisfactory dispersion of light. I may, for example, substitute an edge configuration similar to that illustrated in Fig. 22, wherein the edges of plate 21 are serrated as at 93-93 to form intersecting edge portions preferably at approximately ninety degrees. Thus the light entering one edge passes in a straight line through the plate 21 and is reinforced by light entering from a corresponding opposed edged portion on the opposite edge. The reinforcing or the light rays obtained by this modincation is particularly helpful in large signs since the rays from each illuminated edge reinforce in a criss cross pattern corresponding rays entering from the opposite edge.

It is in some instances desirable to increase the width of the letters or numerals constituting the legend without increasing the thickness of the plate 2!. This I accomplish by forming the various segments of lines making up the legend in the manner illustrated in the Figs. 23 and 24, wherein the base 95 of the groove 92 is made to follow a curved path rather than a relatively straight line, preferably the angle between the sides of the groove 92 being ninety degrees and the curvature interlocking semicircles drawn about aligned points. Thus the total distance encompassed by the line will be twice the width covered by a straight groove. Due to the unusual brilliance of my sign, the legend when illuminated gives the effect of a straight, uniformly broad line, the waviness being undetectable except when the sign is in an unilluminated condition.

In operation it will be found that the legend of my sign is illuminated with a brilliance approaching that attained by neon signs or the like and that the intensity of illumination throughout the legend is remarkably uniform. Since the diameter of the lamp at least approximates the thickness of the sheet, and since the sheets are disposed on opposite sides of the lamp, it may be seen that substantially all of the light is usefully employed and that the cost of operation will therefore be minor. The light rays entering each of the plates are in efiect fanned out parallel to the plane of the plate, some of the rays being intercepted by indicia and other or the rays striking the reflective edges on the plate. 'l'hese rays are renected back into the sign and are eventually intercepted by some portion of the legend. The combined din'racting and reflecting or the light disperses the rays uniformly throughout the sign and provides very even illumination of the legend.

It will of course be obvious to those skilled in the art that the color enects of my sign are practically unlimited and can be varied at will by arrangement of colored films between the source of light and the sign and that blends of colors may be obtained by the use of strips of difi'erent colors applied to either edge of the same plate and interposed between the plate and the source of illumination. Many undescribed permutations and combinations may thus be obtained without departure from my invention and I do not therefore wish to limit myself to the precise details herein disclosed except insofar as defined in the appended claim.

I claim:

A sign comprising a plate of transparent lighttransmitting plastic having a legend engraved thereon, the cross sectional configuration of said legend including a relatively deep central groove portion extending inwardly from the face of the plate a distance not greater than one-half the thickness of the plate and shallow marginal groove portions also extending inwardly irom the same face or the plate and bounding the said central groove portion, whereby the clarity of the legend, when brilliantly illuminated, is increased.

PAUL E. FUCHS.-

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 436,891 Deinerlohr Sept, 23, 1890 576,638 Wasserbach Feb. 9, 1897 1,025,302 Proctor May 7, 1912 1,146,361 Spencer et a1 July 13, 1915 1,440,096 Murray Dec. 26, 1922 1,707,965 Scantlebury Apr, 2, 1929 1,926,389 Fullerton Oct. 6, 1931 1,933,216 Juhasz Oct. 31, 1933 1,984,273 Kuechenmeister Dec. 11, 1934 2,129,651 Cunningham Sept. 13, 1938 2,196,105 Cunningham Apr. 2, 1940 2,207,117 Collins July 9, 1940 2,214,209 Triplett Sept. 10, 1940 2,233,431 Kuehl May 4, 1941 2,262,930 Gasper Nov. 18, 1941 2,454,933 Nash Nov. 30, 1948 FOREIGN PATENTS Number Country Date 191,220 Great Britain Jan. 11, 1923 406,982 Great Britain Feb. 28, 1934 523,706 Great Britain July 19, 1940 593,054 Great Britain Oct. 7, 1947 

